Re: BUG: using smp_processor_id() in preemptible

[Avi Kivity <avi@redhat.com>]

On 06/24/2009 05:15 PM, Johannes Berg wrote:
> Hi,
>
> I'm trying to run a test environment in kvm (because uml doesn't have
> lockdep), and am running into the following problems:
>
> 1) I get the $subject warning a lot, when starting kvm:
> [85763.262707] BUG: using smp_processor_id() in preemptible [00000000] code: kvm/13877
> [85763.262719] caller is kvm_write_guest_time+0x40/0x220 [kvm]
> [85763.262722] Pid: 13877, comm: kvm Not tainted 2.6.30-wl-26837-g0ee651a-dirty #54
> [85763.262725] Call Trace:
> [85763.262729]  [<ffffffff8041d482>] debug_smp_processor_id+0xf2/0x100
> [85763.262741]  [<ffffffffa0331390>] kvm_write_guest_time+0x40/0x220 [kvm]
> [85763.262753]  [<ffffffffa0331890>] vcpu_enter_guest+0x320/0x580 [kvm]
> [85763.262780]  [<ffffffffa03347f4>] __vcpu_run+0x74/0x2f0 [kvm]
> [85763.262792]  [<ffffffffa033571f>] kvm_arch_vcpu_ioctl_run+0x8f/0x200 [kvm]
> [85763.262804]  [<ffffffffa0329b48>] kvm_vcpu_ioctl+0x4b8/0x900 [kvm]
> [85763.262816]  [<ffffffff802f5216>] vfs_ioctl+0x36/0xb0
> [85763.262819]  [<ffffffff802f55f9>] do_vfs_ioctl+0x89/0x320
> [85763.262826]  [<ffffffff802f58df>] sys_ioctl+0x4f/0x80
> [85763.262830]  [<ffffffff8020b6fb>] system_call_fastpath+0x16/0x1b
>
>    

ISTR this was fixed...

> That kernel version is wireless-testing, which is currently based on
> v2.6.30, and the -dirty is for some wireless patches I did.
>    

Please post the output of 'git merge-base wireless-testing 
origin/master' so I can know what tree to look at.

> 2) The second problem is that it doesn't actually work. I use this
> command line:
> kvm -kernel arch/x86_64/boot/bzImage \
> 	-hda ../uml/Ubuntu-IntrepidIbex-amd64-root_fs \
> 	-append "root=/dev/hda console=ttyS0" -curses
>
> and the system hangs after
>                Plex86/Bochs VGABios (PCI) current-cvs 12 Jun 2009
>                This VGA/VBE Bios is released under the GNU LGPL
>
>                Please visit :
>                 . http://bochs.sourceforge.net
>                 . http://www.nongnu.org/vgabios
>
>                cirrus-compatible VGA is detected
>
>                QEMU BIOS - build: 06/12/09
>                $Revision: 1.182 $ $Date: 2007/08/01 17:09:51 $
>                Options: apmbios pcibios eltorito rombios32
>
>                ata0 master: QEMU HARDDISK ATA-7 Hard-Disk (1024 MBytes)
>                ata1 master: QEMU DVD-ROM ATAPI-4 CD-Rom/DVD-Rom
>
>                Press F12 for boot menu.
>
>
>                Decompressing Linux... Parsing ELF... done.
>                Booting the kernel.
>    

Does it hang or switch to some graphics mode?  What happens if you drop 
curses?

You can see where it hangs using the monitor 'info registers' and 'x/30i 
$eip' commands.

> The guest kernel is the same as the host, but with somewhat different
> config options.
>
> The strange thing here is that the exact same command line, with
> qemu-system-x86_64 instead of kvm works perfectly.
>    

That's probably a qemu without kvm support.

-- 
error compiling committee.c: too many arguments to function